Fiber-reinforced resin composition and molded article thereof

ABSTRACT

A fiber-reinforced resin composition comprising: (A) a polyolefin-based resin; (B) glass fibers having (B1) an average diameter of 3 to 30 μm and (B2) an average aspect ratio of 50 to 6000; and (C) an acid-modified polypropylene-based resin exhibiting (C1) a change in amount of acid added, measured by Fourier transform infrared spectroscopy, before and after being treated in methyl ethyl ketone at 70° C. for three hours of 0.8 mass % or less, and having (C2) a melt flow rate (load: 2.16 kg, temperature: 230° C.) of 20 to 2000 g/10 min; the composition containing the components (A) to (C) at such a ratio (mass ratio) that (B):[(A)+(C)]=5 to 80:95 to 20 and (A):(C)=0 to 99.5:100 to 0.5.

TECHNICAL FIELD

The invention relates to a fiber-reinforced resin composition and amolded article produced from the composition.

BACKGROUND ART

Polypropylene exhibits improved strength in the form of glassfiber-reinforced polypropylene (GFPP) prepared by addingaminosilane-treated glass fibers and carboxylic acid group-containingpolypropylene. The strength of long-fiber GFPP prepared using glassfibers with a large aspect ratio is greater than that of short-fiberGFPP. Hence, attention has been paid to the use of long-fiber GFPP forlarge automobile components. For more effective use for automobilestructural components, the long-fiber GFPP is required to exhibit a moreimproved performance. On the other hand, known carboxylic acidgroup-containing polypropylene is still used for preparing GFPP.Extensive studies have not yet been made on carboxylic acidgroup-containing polypropylene which improves the practical performanceof long-fiber GFPP used for structural components or the like.

Studies have been made on the molecular weight or the amount added ofmaleic acid group-containing polypropylene for GFPP. As for by-productsformed at the time of producing carboxylic acid group-containingpolypropylene, studies have been made on improvement of hue as well assuppression of unfavorable odors, but no attention has been paid to theeffect of such by-products on the physical properties (strength) ofGFPP.

In Patent Document 1, in order to improve the hue, studies were made onprovision of a vent in the production line and performing the productionunder reduced pressure. However, this method allows removal of onlyhighly volatile by-products, as the pressure reduction time is not longenough. Further, it is difficult to increase the amount added, andproduction cannot be performed stably (due to occurrence of vent-upproblems). In Patent Documents 2, 3, and 4, attempts were made to reducethe amount of unreacted maleic acid by subjecting 1,2-butadiene to graftpolymerization prior to polypropylene. However, this method could notsuppress formation of by-products.

The above-mentioned studies were made only on short-fiber GFPP with asmall aspect ratio. No attention was paid to the physical properties ofGFPP with a large aspect ratio and high strength.

In Patent Document 5, studies were made on the effect of maleic acidgroup-containing polypropylene on the physical properties of long-fiberGFPP. However, attention was paid only to the fluidity and the acidcontent of the matrix resin, but extensive studies were not made on theeffect of low-molecular-weight maleic acid adducts.

[Patent Document 1] JP-A-7-316239 [Patent Document 2] JP-A-8-12697[Patent Document 3] JP-A-8-134418 [Patent Document 4] JP-A-8-143739[Patent Document 5] JP-A-7-232324

An objective of the invention is to provide a fiber-reinforced resincomposition having a high strength and a molded article produced fromthe composition.

DISCLOSURE OF THE INVENTION

In view of the above-mentioned problems, the invention was made based ona novel finding that high-strength GFPP containing glass fibers with alarge aspect ratio, such as long-fiber GFPP, is significantly affectedby low-molecular-weight maleic acid adducts formed as by-products at thetime of producing a maleic acid-modified polypropylene-based resin.

According to the invention, the following fiber-reinforced resincomposition and molded article produced from the composition areprovided.

1. A fiber-reinforced resin composition comprising:

(A) a polyolefin-based resin;

(B) glass fibers having (B1) an average diameter of 3 to 30 μm and (B2)an average aspect ratio of 50 to 6000; and

(C) an acid-modified polypropylene-based resin exhibiting (C1) a changein amount of acid added, measured by Fourier transform infraredspectroscopy, before and after being treated in methyl ethyl ketone at70° C. for three hours of 0.8 mass % or less, and having (C2) a meltflow rate (load: 2.16 kg, temperature: 230° C.) of 20 to 2000 g/10 min;

the composition containing the components (A) to (C) at such a ratio(mass ratio) that (B):[(A)+(C)]=5 to 80:95 to 20 and (A):(C)=0 to99.5:100 to 0.5.

2. The fiber-reinforced resin composition according to 1; wherein thepolyolefin-based resin (A) is a polypropylene-based resin.3. A molded article produced from the fiber-reinforced resin compositionaccording to 1 or 2.4. A maleic acid-modified polypropylene-based resin exhibiting (C1) achange in amount of acid added, measured by Fourier transform infraredspectroscopy, before and after being treated in methyl ethyl ketone at70° C. for three hours of 0.8 mass % or less, and having (C2) a meltflow rate (load: 2.16 kg, temperature: 230° C.) of 20 to 2000 g/10 min.

According to the invention, a fiber-reinforced resin composition withimproved strength and a molded article produced from the composition canbe provided.

The composition according to invention exhibits a more excellentperformance when a solvent-soluble part is removed.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a view showing a device for producing long fiber-reinforcedresin pellets employed in the examples and the comparative examples.

BEST MODE FOR CARRYING OUT THE INVENTION

The fiber-reinforced resin composition according to the inventioncomprises (A) a polyolefin-based resin, (B) specific glass fibers, and(C) a specific acid-modified polypropylene-based resin.

As the polyolefin-based resin (A), a polypropylene-based resin ispreferred. A propylene homopolymer or an ethylene-propylene blockcopolymer is more preferred. An even more preferable polyolefin-basedresin is a propylene homopolymer.

It is preferable that the polypropylene-based resin (A) meet thefollowing requirements.

The melt flow rate (“MFR”) (temperature: 230° C., load: 2.16 kg) isnormally 1 to 600 g/10 min, preferably 10 to 400 g/10 min, morepreferably 30 to 300 g/10 min, and even more preferably 50 to 150 g/10min. If the melt flow rate of the polypropylene-based resin exceeds 600g/10 min, toughness may be decreased. On the other hand, a melt flowrate of less than 1 g/10 min may result in difficulty in molding.

The crystallinity (mmmm fraction) of the homopolymerized part isnormally 90% or more, preferably 93% or more, and more preferably 96% ormore.

The crystallization temperature (Tc) (B) measured by DSC is normally 80to 130° C., preferably 90 to 125° C., and more preferably 110 to 120° C.

The amount of components with a molecular weight of 1,000,000 or moremeasured by GPC is normally 0.5% or more, preferably 1% or more, andeven more preferably 2% or more. The molecular weight distribution(Mw/Mn) measured by GPC is normally 2 to 10, preferably 2 to 6, andespecially preferably 3 to 5.

The amount of inorganic neutralizer contained in the polyethylene-basedresin is preferably 0.001 to 0.5 mass %, more preferably 0.01 to 0.1mass %, and especially preferably 0.05 mass %. If the amount ofinorganic neutralizer is 0.001 mass % or less, catalyst residues maycause corrosion of a die of a molding machine. On the other hand, if theamount of inorganic neutralizer exceeds 0.5 mass %, the strength of theresin may be lowered. Examples of the inorganic neutralizer includethose described in JP-A-2003-238748. Among them, hydrotarcites areparticularly preferred.

The polypropylene-based resin may be prepared by known methods includingthose disclosed in JP-A-11-71431 and JP-A-2002-249624. For example, byusing a polymerization catalyst, the polypropylene-based resin may beprepared by slurry polymerization, vapor phase polymerization, or liquidphase block polymerization of propylene or the like. A batch orcontinuous polymerization method may be employed.

A commercially available polypropylene-based resin may be employed. Acommercially available polypropylene resin of which the fluidity isadjusted by the addition of an organic peroxide, or a mixture of aplurality of commercially available polypropylene-based resins may alsobe employed. These resins may be employed as the component of the resincomposition or for dilution blending.

Examples of the commercially available propylene-based resin are givenbelow.

1. Propylene-Based Resins Produced by Idemitsu Kosan Co., Ltd. (1)Propylene Homopolymers

J-2003GP (MFR=21), J-2000GP (MFR=21), J-903GP (MFR=13), J-900GP(MFR=13), J-700GP (MFR=8), J-3003GV (MFR=30), J-3000GV (MFR=30),J-3000GP (MFR=30), H-100M (MFR=0.5), H-700 (MFR=7), Y-2000GP (MFR=20),Y-6005GM (MFR=60), E-105GM (MFR=0.5), F-300SV (MFR=3), and Y-400GP(MFR=4)

(2) Propylene-Ethylene Block Copolymers

J-6083HP (MFR=60), J-5066HP (MFR=50), J-5051HP (MFR=50), J-3054HP(MFR=40), J-3056HP (MFR=40), J-950HP (MFR=32), J-762HP (MFR=13), J-466HP(MFR=3), JR3070HP (MFR=30), and J-786HV (MFR=13)

(3) Propylene-Ethylene Random Copolymers

J-3021GA (MFR=30), J-3021GR (MFR=30), and J-2021GR (MFR=20)

2. Polypropylene-Based Resins Produced by SunAllomer, Ltd. (1) PropyleneHomopolymers

PM900M (MFR=30), PM900A (MFR=30), PM802A (MFR=20), PM801Z (MFR=13),PM600Z (MFR=7.5), PM600M (MFR=7.5), PM600H (MFR=7.5), PM600A (MFR=7.5),PF-611 (MFR=30), and PF-814 (MFR=3).

(2) Propylene-Ethylene Block Copolymers

PMB70X (MFR=63), PMB65X (MFR=63), PMB60W (MFR=63), PMB60A (MFR=63),PMA60Z (MFR=45), PMA80X (MFR=43), PMA60A (MFR=43), PM965C (MFR=35),PM953M (MFR=30), and PM761A (MFR=9.5)

(3) Propylene-Ethylene Random Copolymers

PVC20M (MFR=85), PMC20M (MFR=85), PMA20V (MFR=45), PV940M (MFR=30),PM822V (MFR=20), PM811M (MFR=13), and PM731V (MFR=9.5)

3. Polypropylene-Based Resins Produced by Japan PolypropyleneCorporation (Novatec-PP) (1) Propylene Homopolymers

MA3 (MFR=11), MA3AH (MFR=12), and MA03 (MFR=25)

(2) Propylene-Ethylene Random Copolymers

BC06C (MFR=60), BC05B (MFR=50), BC03GS (MFR=30), BC03B (MFR=30), BC03C(MFR=30), BC2E (MFR=16), BC3L (MFR=10), BC3H (MFR=8.5), BC3F (MFR=8.5),and BC4ASW (MFR=5),

BC6DR (MFR=2.5), BC6C (MFR=2.5), and BC8 (MFR=1.8) 4.Polypropylene-Based Resins Produced by Mitsui Chemical, Inc. (MitsuiPolypro) (1) Propylene Homopolymers

J139 (MFR=50), J136 (MFR=20), CJ700 (MFR=10), J108M (MFR=45), J107G(MFR=30), J106G (MFR=15), and J105G (MFR=9)

(2) Propylene-Ethylene Block Copolymers

J709UG (MFR=55), J708UG (MFR=45), J830HV (MFR=30), J717ZG (MFR=32),J707EG (MFR=30), J707G (MFR=30), J715M (MFR=9), J705UG (MFR=9), J704UG(MFR=5), and J702LB (MFR=1.8)

(3) Propylene-Ethylene Random Copolymers

J229E (MFR=52) and J226E (MFR=20)

Examples of the glass fibers (B) employed in the fiber-reinforced resincomposition of the invention include fibers in the form of filamentsprepared by subjecting glass such as electrical glass (E Glass),chemical glass (C Glass), alkali glass (A Glass), high strength glass,or alkali-resistant glass to melt spinning. Of these, electrical glassis preferred.

The average diameter of the glass fibers (B) is 3 to 30 μm, preferably11 to 25 μm, more preferably 14 to 23 μm, and especially preferably 14to 18 μm. If the diameter of the glass fibers is too small, the fiberstend to break, which results in lowered productivity of reinforced resinbundles. In addition, during the continuous production of pellets, thenumber of fibers to be bundled is increased, which leads to a morecomplicated process of combining fiber bundles as well as to loweredproductivity. When the favorable pellet length is specified, if thefiber diameter is too large, the aspect ratio of the fibers is reduced.This may cause the reinforcement effect to deteriorate.

In the case of long-fiber pellets, it is preferred that the pelletlength be 4 to 20 mm and the pellet diameter be 0.5 to 4 mm.

As the long glass fibers, a bundle of continuous glass fibers may beemployed. These fiber bundles are commercially available as a glassroving. Other than the glass roving, a cake described in JP-A-6-114830may be used without restrictions. Glass chopped strands may also beemployed. However, in order to suppress the aspect ratio to the requiredrange, it is preferred to employ glass fiber bundles such as a rovingand a cake.

Glass fibers with a specific cross-sectional shape, such as an ellipse,a cocoon-like shape, and a flat shape, described in JP-A-61-187137,JP-A-61-219732, JP-A-61-219734, JP-A-7-291649, JP-A-7-10591, “SeikeiKakou”, Vol. 15, Issue 9, 2003, page 612 (Yamao et al.), and the likemay be used.

The average aspect ratio of the glass fibers (B) in the resincomposition is 50 to 6000, preferably 75 to 2000, more preferably 100 to1500, and even more preferably 200 to 1000. If the average aspect ratiois too small, the reinforcement effect of the fibers may becomeinsufficient. On the other hand, an excessively large average aspectratio may lead to unstable plasticization during molding and also toinsufficient dispersion of the glass fibers.

To adjust the average aspect ratio of the glass fibers (B) in the resincomposition to 50 or larger, the following means may be employed, forexample. In the case where glass fibers are produced by kneading,restrictions on methods and conditions may be minimized to suppressoccurrence of fiber breakage. Long chopped strands with a length of 6 mmor more may be employed. Glass fibers with a smaller fiber diameter (3to 7 μm) may be also employed. However, it may be difficult to obtain asufficient aspect ratio by these methods. It is common, as well aspreferable, to use long-fiber pellets prepared by drawing or the like.

The glass fibers (B) according to the invention are preferably treatedwith a silane coupling agent, in particular, aminosilane.

Also preferable are glass fibers which have been subjected to sizingtreatment with a urethane-based or an olefin-based emulsion. Inparticular, it is preferred that the glass fibers be treated with aresin emulsion containing the acid-modified polypropylene-based resin(C) of the invention before producing the resin composition.

Examples of the glass roving which may be employed as the glass fibers(B) according to the invention are given below.

1. Glass Roving Produced by Asahi Fiber Glass Co., Ltd.

ER2220 (fiber diameter of 16 μm, treated with an aminosilane couplingagent and an olefin-based emulsion; about 4000 fibers are bundled)

ER740 (fiber diameter of 13 μm, treated with an aminosilane couplingagent and an olefin-based emulsion; about 2000 fibers are bundled)

2. Glass Roving Produced by Nippon Electric Glass Co., Ltd.

ER2310T-441N (fiber diameter of 17 μm, treated with an aminosilanecoupling agent and an olefin-based emulsion; about 4000 fibers arebundled)

3. Glass Roving Produced by Central Glass Co., Ltd.

ERS2310-LF701 (fiber diameter of 17 μm, treated with an aminosilanecoupling agent and a mixed emulsion of a urethane-based emulsion and anolefin-based emulsion; about 4000 fibers are bundled)

ERS2310-LF702 (fiber diameter of 17 μm, treated with an aminosilanecoupling agent and a urethane-based emulsion; about 4000 fibers arebundled)

4. Glass Roving Produced by NSG Vetrotex

RO99 2400 P319 (fiber diameter of 17 μm, treated with an aminosilanecoupling agent and an olefin-based emulsion, about 4000 fibers arebundled)

Examples of commercially available chopped strands are given below.

1. Chopped Strands Produced by Asahi Fiber Glass Co., Ltd.

03 JA FT17 (fiber diameter of 10 μm, treated with an aminosilanecoupling agent and a urethane-based emulsion)

03 MA FT170 (fiber diameter of 13 μm, treated with an aminosilanecoupling and a urethane-based emulsion)

03 JA 486A (fiber diameter of 10 μm, treated with an aminosilanecoupling agent and an epoxy-based emulsion)

03 MA 486A (fiber diameter of 13 μm, treated with an aminosilanecoupling agent and an epoxy-based emulsion)

03 JA FT760A (fiber diameter of 10 μm, treated with an aminosilanecoupling agent and an olefin-based emulsion)

03 MA FT170A (fiber diameter of 13 μm, treated with an aminosilanecoupling agent and an olefin-based emulsion)

2. Chopped Strands Produced by Nippon Electric Glass Co., Ltd.

03T-488DE (fiber diameter of 6 μm, treated with an aminosilane couplingagent and a urethane-based emulsion)

T-480H (fiber diameter of 10.5 μm, treated with an aminosilane couplingagent and an olefin-based emulsion)

T-488 GH (fiber diameter of 10.5 μm, treated with an aminosilanecoupling agent and a urethane-based emulsion)

3. Chopped Strands Produced by NSG Vetrotex

EC10 968 (fiber diameter of 10 μm, treated with an aminosilane couplingagent and an olefin-based emulsion)

EC13 968 (fiber diameter of 13 μm, treated with an aminosilane couplingagent and an olefin-based emulsion)

RES03X-TP15 (fiber diameter of 10 μm, treated with an aminosilanecoupling agent and an olefin-based emulsion)

RES03X-TP B0160 (fiber diameter of 10 μm, treated with anepoxysilane/aminosilane coupling agent and an epoxy-based emulsion)

4. Chopped Strands Produced by Nittobo Co., Ltd.

CS 3J-956 (fiber diameter of 11 μm, treated with an aminosilane couplingagent and an acryl-based emulsion)

CS 3J-254 (fiber diameter of 13 μm, treated with an aminosilane couplingagent and an acryl-based emulsion)

CS 3PE-956 (fiber diameter of 11 μm, treated with an aminosilanecoupling agent and a urethane-based emulsion)

The acid-modified polypropylene-based resin (C) to be used in thefiber-reinforced resin composition according to the invention isprepared by modifying a polypropylene-based resin with an acid. As theacid, a carboxylic acid or derivatives thereof is preferable. It isespecially preferable that the polypropylene-based resin be modifiedwith maleic acid.

As the polypropylene-based resin used as the starting material for theacid-modified polypropylene-based resin, a propylene homopolymer or anethylene-propylene random copolymer is preferable. The most preferablepolypropylene-based resin is a propylene homopolymer.

The melt flow rate of the polypropylene-based resin used as the startingmaterial for the acid-modified polypropylene-based resin is normally0.05 to 20 g/10 min, preferably 0.1 to 10 g/10 min, more preferably 0.2to 4 g/10 min, and even more preferably 0.3 to 2 g/10 min.

As the polypropylene-based resin used for the acid-modifiedpolypropylene-based resin, the resins given as examples of thepolyolefin-based resin (A) may be employed.

Examples of the acid for use in modification include carboxilic acidsand derivatives thereof, such as acetic acid, acrylic acid, malonicacid, succinic acid, maleic acid, fumaric acid, benzoic acid,2-naphthoic acid, phthalic acid, iso-phthalic acid, terephthalic acid,isonicotinic acid, 2-furoic acid, formic acid, propionic acid, propiolicacid, butyric acid, iso-butyric acid, methacrylic acid, palmitic acid,stearic acid, oleic acid, oxalic acid, glutalic acid, adipic acid,cinnamic acid, glycolic acid, lactic acid, glyceric acid, tartaric acid,citric acid, glyoxylic acid, pyruvic acid, acetoacetic acid, benzylacid, anthranic acid, and ethylenediamine tetraacetic acid. Of these,dicarboxlic acids are preferable. Especially preferable is maleic acid.

As the method for producing the acid-modified polypropylene-based resin,known methods described in JP-A-8-143739, JP-A-2002-20560,JP-A-7-316239, JP-A-8-127697 and JP-A-7-232324 may be used.

For example, a solution method in which an organic peroxide, maleicacid, and polypropylene are reacted in a solvent; a melt method in whichan organic peroxide, maleic acid, and polypropylene are melt kneaded;and a thermal decomposition method in which thermally decomposedpolypropylene is reacted with maleic acid may be employed. The solutionmethod has a disadvantage in that, as a side reaction with an organicsolvent is likely to occur, the organic solvent tends to remain as aresidue. The thermal decomposition method has a drawback in which themolecular weight distribution of the resulting polypropylene tends to betoo large. For these reasons, the melt method is preferable.

Known reaction initiators, such as organic peroxides, may be used forthe production of the acid-modified polypropylene-based resin.

An organic peroxide as referred to herein is a derivative of hydrogenperoxide (H—O—O—H) having a structure in which one or two hydrogen atomsof the hydrogen peroxide may be replaced with an organic free radical.The organic peroxide is characterized by the presence of a peroxide bond“O—O” in its molecule.

Typical examples of usable organic peroxides include dialkyl peroxides,ketone peroxides, diacyl peroxides, hydroperoxides, peroxyl ketals,alkyl peresters, and percarbonates. Of these, diacyl peroxides arepreferable.

Preferable diacyl peroxides include1,3-bis-(t-butylperoxyisopropyl)benezene, for example, Perkadox 14,Bisblake P, AD-2, and Perkadox 14-C (produced by Kayaku Akzo Corp.),2,5-dimethyl-2,5-di-(t-butylperoxy)heptane,3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane, for example,Trigonox 301 (produced by Kayaku Akzo Corp.), and di-t-butylperoxide,for example, Kaybutyl D (produced by Kayaku Akzo Corp.). Of these,1,3-bis-(t-butylperoxyisopropyl)benzene is especially preferable inrespect of the half life, odor, and color balance.

Normally, an organic peroxide of which the half life is one minute at atemperature of 90 to 200° C. is employed. An organic peroxide of whichthe half life is one minute at a temperature of 120 to 200° C. ispreferable, 150 to 200° C. is more preferable, and 160 to 200° C. isespecially preferable. The active hydrogen content of the organicperoxide is normally 2 to 12%, and preferably 3 to 6%. If thetemperature at which the half life of the organic peroxide is one minuteis lower than 90° C., the organic peroxide deactivates quickly,resulting in insufficient reaction. It is hard to find an organicperoxide on the market of which the half life is one minute at atemperature higher than 200° C.

The acid-modified polypropylene-based resin (C) according to theinvention shows a change in the amount of acid added, measured byFourier transform infrared spectroscopy, before and after being treatedin methyl ethyl ketone at 70° C. for three hours of 0.8 mass % or less,preferably 0.4 mass % or less, more preferably 0.3 mass % or less, stillmore preferably 0.18 mass % or more, particularly preferable 0.08 mass %or less, and most preferably 0.02 mass % or less.

A small change in the amount of acid added indicates a low content oflow-molecular-weight maleic acid adducts.

The detailed composition of the low-molecular-weight maleic acid adducthas not yet been fully elucidated. It can be anticipated that thelow-molecular-weight maleic acid adduct includes a polypropyleneoligoner to which maleic acid is added, an organic peroxide, across-linking agent or a solvent to which maleic acid is added, orunreacted maleic acid.

Preferred methods for removing low-molecular-weight maleic acid adductsinclude, but are not limited to, degasification, washing, andpurification. Since it is difficult to remove low-volatile components bydegasification, washing or purification is more preferred. An especiallypreferred method is washing with a heated solvent at 30 to 120° C.

(1) Degasification

After reducing the pressure through a vent at the time of extrusion, theacid-modified polypropylene-based resin is heated under reduced pressure(vacuum) and dried with hot air.

(2) Washing

Use of a washing solvent such as methyl ethyl ketone and anacetone/heptane mixed solution is preferred (it is preferred that thewashing solvent be heated to 30 to 120° C., and more preferably 60 to110° C.). After washing with the solvent, separation and drying areperformed. Other employable methods include washing with steam, hotwater, and water. It is efficient to wash with the washing solvent.

(3) Purification

The acid-modified polypropylene-based resin is dissolved in a heatedsolvent (paraxylene, xylene, toluene, benzene, n-heptane, chlorobenzene,or the like), and precipitated using reprecipitation solvent (acetone,acetone/methanol mixture, or the like). After filtration, drying isperformed by, for example, vacuum drying.

The amount of acid added to the acid-modified polypropylene-based resin(part insoluble in methyl ethyl ketone) is normally 0.4 to 10 mass %,preferably 0.7 to 2.9 mass %, more preferably 0.7 to 1.8 mass %, evenmore preferably 0.9 to 1.8 mass %, and especially preferably 0.9 to 1.5mass %. If the amount of acid added is less than 0.4 mass %, thestrength of the resin may be insufficient. If the amount of acid addedexceeds 10 mass %, the melt flow rate may increase or it may bedifficult to remove soluble matters.

The change rate of the amount of acid added before and after 3-hourtreatment of the film with methyl ethyl ketone at 70° C. [=change in theamount of acid added before and after the treatment/the amount of acidadded after treatment] is normally 0.4 or less, preferably 0.3 or less,more preferably 0.2 or less, even more preferably 0.1 or less, andespecially preferably 0.05 or less.

The melt flow rate (MFR) of the acid-modified polypropylene-based resin(measured according to ASTM D-1238, at a load of 2.16 kg and atemperature of 230° C.) is 20 to 2000 g/10 min, preferably 60 to 1500g/10 min, more preferably 130 to 1000 g/10 min, even more preferably 260to 750 g/10 min, and especially preferably 260 to 550 g/10 min.

If the melt flow rate is 600 g/10 min or more, the measurement accuracywill be lowered. Therefore, in such a case, measurement is performed ata load of 1.05 kg and a temperature of 190° C., and the measurementresult is converted by the following formula.

MFR(230° C., 2.16 kg)=6.2×MFR(190° C., 1.05 kg)

If the melt flow rate of the acid-modified polypropylene-based resinexceeds 2000 g/10 min, strength and durability may be lowered. The meltflow rate of less than 20 g/10 min may lead to lowered strength anddeteriorated appearance.

The methods for adjusting the melt flow rate of the acid-modifiedpolypropylene-based resin (maleic acid-modified polypropylene-basedresin) include changing the molecular weight of polypropylene(JP-A-2002-20560), changing the reaction temperature, changing theconcentrations of maleic acid and an organic peroxide, adding across-linked polymer (e.g. polybutadiene) (JP-A-8-143739), and adding apolyfunctional compound.

The number average molecular weight (Mn) of the acid-modifiedpolypropylene-based resin measured by GPC is normally 12,000 to 60,000,preferably 14,000 to 55,000, more preferably 16,000 to 50,000, even morepreferably 18,000 to 46,000, especially preferably 23,000 to 38,000, andmost preferably 26,000 to 34,000.

The molecular weight distribution Mw/Mn measured by GPC is normally 2 to10, preferably 2 to 4, and especially preferably 2.5 to 3.5.

The content of components with a molecular weight of 20,000 or lessmeasured by GPC is normally 40% or less, preferably 30% or less, andespecially preferably 20% or less.

The content of components with a molecular weight of 5,000 or lessmeasured by GPC is normally 10% or less, preferably 6% or less, morepreferably 4% or less, and especially preferably 3% or less.

The average number of functional groups per molecule of theacid-modified polypropylene-based resin obtained from the amount offunctional groups added measured by FT-IR and the number averagemolecular weight measured by GPC is normally 1.5 to 12(number/molecule), preferably 1.5 to 6, more preferably 1.5 to 4, evenmore preferably 2 to 4, and especially preferably 2.4 to 3.6.

If the average number of functional groups per molecule exceeds 12(number/molecule), the strength may be lowered, as the resin tends to bebonded to the glass fiber surface at a number of points. On the otherhand, if the average number of functional groups per molecule is lessthan 1.5 (number/molecule), a propylene-based resin with no maleic acidgroup added may be unexpectedly formed, resulting in lowered efficiency.

The limiting viscosity of the acid-modified polypropylene-based resin(measured in tetralin at 135° C.) is normally 0.4 to 1.8, preferably 0.4to 1.1, more preferably 0.40 to 1.05, even more preferably 0.50 to 1.00,and especially preferably 0.60 to 0.95.

The crystallinity (mmmm fraction) of the acid-modifiedpolypropylene-based resin is normally 85 to 99.9%, preferably 88 to 98%,and especially preferably 90 to 94%.

The crystallization temperature (Tc) (C) of the acid-modifiedpolypropylene-based resin measured by DSC is normally 80 to 130° C.,preferably 90 to 125° C., and more preferably 110 to 120° C. It ispreferred that the conditions defined by the formula: Tc(C)<Tc(B)−5° C.be satisfied.

The amount of residual peroxides of the acid-modifiedpolypropylene-based resin is normally 1,000 ppm or less, preferably 500ppm or less, even more preferably 100 ppm or less, and especiallypreferably 50 ppm or less.

The yellow index (YI: measured according to JIS K7105-1981) of theacid-modified polypropylene-based resin is normally 0 to 80, preferably0 to 50, and especially preferably 0 to 20. If the yellow index exceeds80, the molded article may yellow, which results in a deterioratedappearance.

The ring-opening ratio of the maleic acid group of the acid-modifiedpolypropylene-based resin measured by FT-IR is normally 80% or less,preferably 70% or less, and more preferably 50% or less. If thering-opening ratio exceeds 80%, the ring-opened maleic acid group mayundergo a ring-closing reaction during molding to produce water, causingsilver streaks to be formed. This causes the appearance to deteriorate.

The content of low-molecular-weight components of the acid-modifiedpolypropylene-based resin (the content oflow-molecular-weight-components is measured by a method in which thecomponents are dissolved in xylene, the resulting slurry is washed withacetone, the washing solution is then subjected to condensation andevaporation to dryness, and the dryness is measured) is normally 3 mass% or less, preferably 0.5 mass % or less, more preferably 0.3 mass % orless, and especially preferably 0.1 mass % or less.

The volatile content of the acid-modified polypropylene-based resin(comparison is made on the weights before and after overdrying) isnormally 0.5 mass % or less, preferably 0.3 mass % or less, morepreferably 0.1 mass % or less, even more preferably 0.05 mass % or less,and especially preferably 0.02 mass % or less. If the volatile contentexceeds 0.5 mass %, unpleasant odors may be generated and the appearancemay become poor (occurrence of gas whirling).

The amount of gel of the acid-modified polypropylene-based resin (theamount of components which do not pass through a 5μ millipore filteraccording to the melt pressure penetration method) is normally 2 mass %or less, preferably 1 mass % or less, more preferably 0.5 mass % orless, and especially preferably 0.2 mass % or less. An amount exceeding2 mass % may result in a deteriorated appearance.

The ratio of the polyolefin-based resin (A), the glass fibers (B), andthe acid-modified polypropylene-based resin (C) in the fiber-reinforcedresin composition of the invention is (B):[(A)+(C)]=5 to 80:95 to 20,preferably 10 to 70:90 to 30, and more preferably 35 to 55:65 to 45.

In addition, (A):(C) is normally 0 to 99.5:100 to 0.5, more preferably80 to 99:20 to 1, even more preferably 90 to 98:10 to 2, and especiallypreferably 94 to 98:6 to 2.

Various known additives may be added to the composition of the inventiondepending on the application. Examples of such additives includeadditives for modification including dispersants, lubricants,plasticizers, mold releasing agents, flame retardants, antioxidants(phenol-based antioxidants, phosphorus-based antioxidants, andsulfur-based antioxidants), antistatic agents, light stabilizers, UVabsorbers, metal inerting agents, crystallization accelerators(nuclei-forming agents), alkaline earth metal compounds such asmagnesium hydroxide and aluminum hydroxide, additives for modificationsuch as foaming agents, cross-linking agents, and antibacterial agents;coloring agents including carbon black, zinc sulfide, pigment, and dye;fillers in the form of powder such as titanium oxide, red iron oxide,azo pigments, anthraquinone pigments, phthalocyanine, talc, calciumcarbonate, mica, clay, graphite, and glass flake; short-fiber fillersincluding wallastonite and milled fibers; organic fillers includingcellulose, bamboo fibers, and aramid fibers; and whiskers includingpotassium titanate.

Various elastomers may be added to the composition according to theinvention depending on the application. As olefin-based elastomers,elastomers described in JP-A-2002-3616 may be employed, for example.

The fiber-reinforced resin composition according to the invention may beused in the form of a mat (glass mat sheet), a prepreg, resin pellets,or the like. It is preferred that the resin composition be in the formof resin pellets which can be readily molded.

The method of producing the fiber-reinforced resin composition of theinvention is described below.

It is preferred that the fiber-reinforced resin composition belong-fiber pellets, which may be prepared by the methods described inJapanese Patent No. 3234877 or in a document titled “Seikei Kakou”, Vol.5, Issue 7, page 454 (1993) or by other known methods. For example, themethod described below may be employed.

Long-fiber reinforced-resin pellets may be prepared readily byintroducing a roving consisting of thousands of reinforcement fibersinto an impregnation die where the filaments are uniformly impregnatedwith the molten polyolefin-based resin. The pellets are then cut into arequired length.

For example, while the molten resin is supplied from an extruder to animpregnation die provided at the front of the extruder, a continuousglass fiber bundle is caused to pass through to impregnate the glassfiber bundle with the molten resin. Then, the molten resin is withdrawnthrough a nozzle, and pelletized to a specific length. It is alsopossible to employ a method including dry-blending a polyolefin-basedresin, modifier, organic peroxide, and the like and sending the blendinto the hopper of an extruder so that modification and supply can beperformed simultaneously.

There is no restriction on the method of impregnation. Examples ofemployable methods include: a method in which a roving is caused to passthrough a resin powder fluidized bed, and the roving is heated to atemperature higher than the melting point of the resin (JP-A-46-4545); amethod in which a reinforced fiber roving is caused to pass through apolyolefin-based powder fluidized layer so that the polyolefin-basedresin powder is attached to the roving, the roving is heated to atemperature higher than the melting point of the polyolefin-basedresin(JP-A-46-4545); a method in which a reinforced fiber roving isimpregnated with a molten polyolefin-based resin by means of a crosshead die (JP-A-62-60625, JP-A-63-132036, JP-A-63-264326, andJP-A-1-208118); a method in which resin fibers and reinforced fiberresin rovings are mixed and heated to a temperature higher than themelting point of the resin (JP-A-61-118235); a method in which a numberof rods are arranged inside the die, a roving is wound around each rodin a zig-zag manner to open the fibers and impregnate the roving withthe resin (JP-A-10-264152); a method in which a roving is caused to passthrough a pair of opened fiber pins while avoiding contact of the rovingwith the pin (WO97/19805); a method in which strands of roving areformed by means of a roller (JP-A-5-169445); a method in which a mixtureof glass fibers and a polyolefin-based resin is prepared and then heated(NSG Vetrotex); a method utilizing intake air (JP-A-9-323322); and amethod in which variations of glass filament diameters are suppressedwithin a specific range (JP-A-2003-192911). Any of the above methods canbe employed.

Glass fibers with a specific cross-sectional shape (an ellipse shape, acocoon-like shape, or a flat shape) are preferable to attain sufficientimpregnation.

Short-fiber reinforced pellets may be prepared by subjecting part or allof the components (A) to (C) to melt kneading. The aspect ratio isadjusted to a desired range by selecting the type of glass fibers as thestarting material, by adjusting the kneading conditions, or the like.For example, adjusting the rotational speed of a screw or using a screwwhich does not break the fibers may be employed.

The molded article according to the invention may be prepared by a knownmethod including injection molding, extrusion molding, hollow molding,compression molding, injection/compression molding, gas-assistedinjection molding, or foam injection molding. Of these, injectionmolding, compression molding, and injection/compression molding arepreferable.

The molded article according to the invention may be used for injectionmolding compounds including in-line compounds and direct compounds asdescribed in Plastics Info World 11/2002, pages 20 to 35.

Normally, since the fibers tend to break during molding, the averageaspect ratio of the fibers in the molded article is likely to be smallerthan the average aspect ratio of the fibers in the composition. Theaspect ratio of the fibers in the molded article is normally 40 to 2000,preferably 60 to 1000, even more preferably 75 to 750, and especiallypreferably 100 to 500. If the average aspect ratio is less than 40, thestrength of the molded article may be insufficient. On the other hand,if the average aspect ratio exceeds 2000, the appearance may deterioratedue to insufficient dispersion.

The molded article may be prepared by molding the resin compositionaccording to the invention or molding the composition after blendingwith a diluent. The fiber-reinforced resin pellets and a diluent (e.g. apolyolefin-based resin similar to the fiber-reinforced resin pellets)may be blended by dry blending. To maintain the fiber length in thecomposition and to attain improvement in toughness, impact resistance,and durability, it is preferred that the dry blend of fiber-reinforcedresin pellets and a diluent be directly supplied to a molding devicesuch as an injection molding device without supplying the dry blend toan extruder. The amount of diluent varies depending on the content ofthe reinforcement fibers in the fiber-reinforced resin pellets and therequired content of the reinforcement fibers in the final moldedarticle. In view of the improvement in toughness, impact resistance, anddurability, the amount of diluent is preferably 20 to 85 wt %.

EXAMPLES

The following components (A) to (C) were employed in the examples andthe comparative examples.

1. Polyolefin-Based Resin (A)

PP-A: J-3000GV (polypropylene homopolymer with a melt flow rate of 30,produced by Idemitsu Kosan Co., Ltd., which had been decomposed withPerkadox 14 (peroxide) to adjust the melt flow rate to 80)PP-B: J-6083HP (propylene-ethylene block copolymer with a melt flow rateof 60, produced by Idemitsu Kosan Co., Ltd.)

2. Glass Fibers (Reinforcement Fibers) (B)

GF-1: ER2220 (glass roving with an average fiber diameter of 16 μm whichhad been treated with an aminosilane coupling agent and an olefin-basedemulsion, produced by Asahi Fiber Glass Co., Ltd.)GF-2: 03 JA FT17 (chopped strand of 3 mm in length, with an averagefiber diameter of 10 μm, which had been treated with an aminosilanecoupling agent and a urethane-based emulsion, produced by Asahi FiberGlass Co., Ltd.)GF-3: T-480H (chopped strand of 3 mm in length, with an average fiberdiameter of 10.5 μm, which had been treated with an aminosilane couplingagent and an olefin-based emulsion, produced by Asahi Fiber Glass Co.,Ltd.)

3. Maleic Acid-Modified Polypropylene-Based Resin (C)

3-1. Acid-modified polypropylene-based resins C-1 to C-12 having theproperties shown in Table 1 were employed.(1) The amounts (a) and (b) of maleic acid added were measured by thefollowing methods.

(i) Amount (b) of Maleic Acid Added to Maleic Acid-ModifiedPolypropylene-Based Resin

By using dodecasuccinic acid and polypropylene powder for adjusting theconcentration (product name: H-700, produced by Idemitsu Kosan Co.,Ltd), the peak area was plotted against the amount of maleic acid toobtain a calibration curve.

Subsequently, the sample was pre-heated at 230° C. for 10 minutes by hotpressing, pressed for 4 minutes (5 Mpa), and pressed for 3 minutes bycold pressing (5 Mpa) to obtain a film with a thickness of about 0.1 mm.

A part of the resulting film (15 mm×20 mm×0.1 mm) was washed byimmersing in 10 ml of methyl ethyl ketone (MEK) at 70° C. for 3 hours.Then, the film was removed, air-dried, and vacuum dried at 130° C. for 2hours.

Within 2 hours after the drying, the FT-IR transmission spectrum wasobtained, and the peak area at 1670 to 1810 cm⁻¹ of the FT-IR spectrumwas calculated. The peak area was compared with the above-obtainedcalibration curve to obtain the amount (b) of carboxylic acid groupadded to the maleic acid-modified polypropylene-based resin.

(ii) Total Amount (a) of Maleic Acid Added

By using dodecasuccinic acid and polypropylene powder for adjustingconcentration (product name: H-700, produced by Idemitsu Kosan Co.,Ltd), the peak area was plotted against the amount of maleic acid toobtain a calibration curve.

Subsequently, the sample was pre-heated at 230° C. for 10 minutes by hotpressing, pressed for 4 minutes (5 Mpa), and pressed for 3 minutes bycold pressing (5 Mpa) to obtain a film with a thickness of about 0.1 mm.

Within 2 hours after the preparation of the film, the FT-IR spectrum ofthe film was measured, and the peak area at 1670 to 1810 cm⁻¹ of theFT-IR spectrum was calculated. The peak area was compared with theabove-obtained calibration curve to obtain the total amount of maleicacid added. The amount (b) of maleic acid in the maleic-acid modifiedpolypropylene-based resin obtained in (i) above was subtracted from thetotal amount (a) of maleic acid added to obtain the amount (a-b) oflow-molecular weight maleic acid adducts added to carboxylic acidgroups.

(2) The number average molecular weight (Mn), the weight averagemolecular weight (Mw), and the molecular weight distribution (Mw/Mn)shown in Table 1 were obtained, according to the method described inJP-A-11-71431, from the polystyrene-reduced molecular weightdistribution curve by gel permeation chromatography (GPC).

The measuring conditions are as follows.

Calibration curve: Universal Calibration

Column: TOSOH GMHHR-H(S) HT×2

Solvent: 1,2,4-trichlorobenzene

Temperature: 145° C.

Flow rate: 1.0 ml/minDetector: RI (Waters alliance GPC2000)Analysis program: HTGPC (version 1.00)

The melt flow rate (MFR) was measured according to ASTM D-1238 (load:2.16 kg, temperature: 230° C.).

If the melt flow rate is 600 g/10 min or more, the measurement accuracywill be lowered. Therefore, in such a case, measurement is performed ata load of 1.05 kg and a temperature of 190° C., and the measurementresult is converted by the following formula.

MFR(230° C., 2.16 kg)=6.2×MFR(190° C., 1.05 kg)

(3) The number of functional groups per molecule shown in Table 1 wasmeasured according to the following method.

Number of functional groups per molecule=(0.01×A÷Mr)÷(1÷Mn)=0.1×A×Mn/Mr

where A represents the amount of functional groups added (mass %), Mrrepresents the molecular weight of the functional groups, and Mnrepresents the number average molecular weight of the acid-modifiedpolypropylene-based resin. For example, the number of maleic acid groups(Mr=98) per molecule is almost equal to A×Mn/10,000.

TABLE 1 C-1 C-2 C-3 C-4 C-5 C-6 C-7 C-8 C-9 C-10 C-11 C-12 Amount (a)Mass % 1.20 1.21 2.47 0.96 1.55 3.85 1.55 2.85 4.00 2.10 4.00 1.20Amount (b) Mass % 1.20 1.20 2.45 0.95 1.20 3.50 0.95 2.10 2.50 1.20 2.450.30 (insoluble in MEK) Amount of Mass % 0.00 0.01 0.02 0.01 0.35 0.350.60 0.75 1.50 0.90 1.55 0.90 low-molecular- weight maleic acid adducts(a) − (b) Number average ×10³ 28 28 36 45 28 24 20 20 9 28 36 52molecular weight (Mn) Weight average ×10³ 76 76 100 132 76 68 61 98 3576 100 190 molecular weight (Mw) Mw/Mn — 2.71 2.71 2.78 2.93 2.71 2.833.05 4.90 3.89 2.71 2.78 3.65 MFR (load: 2.16 kg, g/10 min 540 540 260140 540 810 990 990 2290 540 290 120 temperature: 230° C.) MFR (load:1.05 kg, g/10 min — — — — — 130 160 160 370 — — — temperature: 190° C.)Limiting viscosity dl/g 0.62 0.62 0.78 0.92 0.62 0.53 0.49 0.49 0.330.62 0.76 0.95 (η) (135° C., in tetralin) Number of Number 3.4 3.4 8.84.3 3.4 8.4 1.9 4.2 2.3 3.4 8.8 1.6 functional groups per molecule3-2. The acid-modified polypropylene-based resins C-1 to C-12 wereproduced by the following method. The ratio and production conditions ofthe acid-modified polypropylene-based resins C-1 to C-5, C-7, C-8, andC-10 to C-12 are shown in Table 2.

In the table, PP-1 is a polypropylene homopolymer (PP) with an MFR of0.5 (H-100M, produced by Idemitsu Kosan, Co., Ltd.) and PP-2 is apolypropylene homopolymer with an MFR of 7 (H-700, produced by IdemitsuKosan, Co., Ltd.). As for peroxides shown in the table, X-1 is Perkadox14 (produced by Kayaku Akzo Corp.) and X-2 is2,5-dimethyl-2,5-di(t-butylperoxy)hexine-3.

[C-9]

Commercially available Umex 1001 (produced by Sanyo Chemical Industries)was employed without modification.

[C-1]

C-1 was manufactured and purified according to the following method.

Using a twin-screw extruder provided with a vent, C-1 was manufacturedby the melt method under the conditions shown in Table 2. Then, afunctional group-containing polyolefin-based resin was heated inparaxylene (130° C.) with stirring to completely dissolve the resin. Theresulting solution was reprecipitated in acetone, filtered, andvacuum-dried (at 130° C. for about 6 hours).

[C-2 to C-5]

C-2 to C-5 were prepared under the conditions shown in Table 2 andwashed.

The method for washing C-2, C-3, and C-4 was as follows.

Using a twin-screw extruder provided with a vent, C-2, C-3 and C-4 weremanufactured by the melt method under the conditions shown in Table 2.Then, 1 kg of each sample was washed in a mixed solution of acetone (3l) and heptane (3 l) in a 10 l-capacity autoclave at 85° C. for 2 hours.The liquid was then removed and allowed to stand in 10 l of acetone for12 hours. After removing the liquid, the liquid was vacuum-dried at 130°C. for 6 hours.

C-5 was washed in the same manner as in the case of C-2 to C-4, exceptthat the temperature of the washing solution (mixed solution) waschanged to 55° C.

[C-6]

100 phr of a polypropylene homopolymer (MFR=7 g/10 min., crystallinity:94%, H-700, produced by Idemitsu Kosan, Co., Ltd.), 2 phr ofpolybutadiene (cross-linking agent, R-45HT, produced by Idemitsu KosanCo., Ltd.), 10 phr of maleic anhydride, and 0.5 phr of an organicperoxide (Perbutyl D (di-t-butylperoxide), produced by Kayaku AkzoCorp.) were put in toluene (reaction solvent) so that the polymerconcentration became 300 g/l. The mixture was incorporated into anautoclave with a capacity of 2.3 l. The mixture was heated (from normaltemperature to 145° C. for 2 hours), reacted (145° C.), and cooled (30min). The resin was transferred into 2 l of methyl ethyl ketone. Theresin transferred into methyl ethyl ketone was then subjected tocentrifugation, washed with methyl ethyl ketone of normal temperature(23° C.), and vacuum dried at 60° C. for 24 hours.

[C-7, C-8, and C-10 to C-12]

C-7, C-8, and C-10 to C-12 were prepared by the melt method using atwin-screw extruder provided with a vent under the conditions shown inTable 2. Washing was not performed.

TABLE 2 Top feed blending Side feed blending Kneading conditionsPolypropylene Maleic acid Peroxide Polypropylene Maleic acid ChargingMethod for Rotational Temperature Part by Part by Part by Part by Partby rate Method removal speed (rpm) (° C.) weight weight weight weightweight Top/Side C-1 Melt Purification 300 170 PP-1 100 6 X-1 1.2 0 0 1/0method C-2 Melt Washing 300 170 PP-1 100 6 X-1 1.2 0 0 1/0 method C-3Melt Washing 250 180 PP-1 100 13 X-1 5.2 PP-1 100 9 1/1 method C-4 MeltWashing 100 180 PP-1 100 6 X-1 2.4 PP-1 100 1/1 method C-5 Melt Washing300 170 PP-1 100 6 X-1 1.2 0 1/0 method C-7 Melt None 100 180 PP-1 1003.5 X-1 0.6 PP-1 100 0 1/1 method C-8 Melt None 250 180 PP-1 100 13 X-15.2 PP-1 100 0 1/1 method C-10 Melt None 300 170 PP-1 100 6 X-1 1.2 0 01/0 method C-11 Melt None 250 180 PP-1 100 13 X-1 5.2 PP-1 100 9 1/1method C-12 Melt None 100 180 PP-2 100 2 X-2 0.3 0 1/0 method

Examples 1 to 8 and Comparative Examples 1 to 4

Compositions and comparative compositions were prepared using a deviceshown in FIG. 1.

The molten polypropylene-based resin (A) and the acid-modifiedpolypropylene-based resin (C) were supplied at a ratio (mass ratio)shown in Table 3 from an extruder 7 to an impregnation die 3. The fiberbundle withdrawn from the glass roving (B)1 was introduced into theimpregnation die 3 filled with the polypropylene-based resin (A) and theacid-modified polypropylene-based resin (C). The glass fiber bundle wasimpregnated with the resin component at a fiber withdraw rate of 15m/min and a resin temperature of 280° C. The resulting product was thenpelletized using a cooling bath 9, a withdrawer 11, and a pelletizer 13to obtain pellets (GMB-1 to 12) 15. The cross section of the die 5 wascircular and had a diameter of 2.3 mm.

The resulting pellets had a major-axis diameter of 2.3 mm, a minor-axisdiameter of 1.9 mm, a pellet length of 8 mm, and a glass fiber contentof 40 mass %.

From the resulting pellets, samples for injection molding were preparedaccording to the method specified in JIS K 7152-1:1999. The physicalproperties were measured and evaluated according to the followingmethods.

(1) Tensile Stress at Break (23° C.)

Measured according to JIS K 7161-1994.

(2) Bending Strength (23° C.)

Measured according to JIS K 7171-1994.

(3) Flexural Modulus (23° C.)

Measured according to JIS K 7171-1994.

(4) Charpy Impact Strength (23° C., without Notch)

Measured according to JIS K 7111-1996.

(5) Falling-Ball Cracks (1.9 kg)

A flat plate (140×140×3 mm) was prepared and secured using a jig. A ballweighing 1.9 kg was dropped to measure the height at which cracks wereproduced on the backside of the plate.

(6) Weight Average Fiber Length

After incineration in an electric furnace, the lengths of 500 to 2000fibers were measured using an image processor (produced by Luzex Co.,Ltd.), and the weight average fiber length was calculated as follows.

Σ(fiber length)²/Σ(fiber length)

(7) Average Aspect Ratio

The average fiber diameter was measured using an electron microscope.

The average aspect ratio of the fibers in the composition was calculatedby dividing the average fiber length by the average fiber diameter.

The evaluation results are shown in Table 5.

Examples 9 and 10 and Comparative Examples 5 and 6

The pellets (GMB-13 to GMB-16) were prepared in the same manner as inExample 1, except that the amount ratios were changed to those shown inTable 3.

The resulting pellets, a polypropylene-based resin (PP-A, PP-B) as adiluent, and an elastomer (A1050S, produced by Mitsui Chemicals, Inc.)were mixed at ratios shown in Table 4 to obtain blends (GBD-1 to GBD-4).

The evaluation was performed in the same manner as in Example 1. Theresults are shown in Table 5.

Comparative Examples 7 to 10

Short-fiber pellets were prepared using the materials in amounts(massratio) shown in Table 6.

A twin-screw kneader (TEM20, produced by Toshiba Machine, Co., Ltd.) wasused for kneading at a cylinder temperature of 200° C. and a screwrotational speed of 350 rpm. A propylene homopolymer and anacid-modified polypropylene-based resin were subjected to dry blending,and the resulting blend was fed from the top. Glass fibers were fed fromthe side. The total supply amount was 30 kg/hr. After cooling withwater, the strands were cut by means of a pelletizer to obtainglass-fiber reinforced resin pellets.

The evaluation was performed in the same manner as in Example 1. Theresults are shown in Table 6.

TABLE 3 GMB-1 GMB-2 GMB-3 GMB-4 GMB-5 GBM-6 GMB-7 GMB-8 GMB-9 (A) TypePP-A PP-A PP-A PP-A PP-A PP-A PP-A PP-A PP-A Mass % 59 59 59 59 59 59 5959 59 (B) Type GF-1 GF-1 GF-1 GF-1 GF-1 GF-1 GF-1 GF-1 GF-1 Mass % 40 4040 40 40 40 40 40 40 (C) Type C-1 C-2 C-3 C-4 C-5 C-6 C-7 C-8 C-9 Mass % 1  1  1  1  1  1  1  1  1 GMB-10 GMB-11 GMB-12 GMB-13 GMB-14 GMB-15GMB-16 (A) Type PP-A PP-A PP-A PP-A PP-A PP-B PP-B Mass % 59 59 59 48 4848 48 (B) Type GF-1 GF-1 GF-1 GF-1 GF-1 GF-1 GF-1 Mass % 40 40 40 50 5050 50 (C) Type C-10 C-11 C-12 C-2 C-9 C-2 C-9 Mass %  1  1  1  2  2  2 2

TABLE 4 GBD-1 2 3 4 GFMB Type GMB-13 14 15 16 Mass % 80 80 80 80 PP TypePP-A PP-A PP-B PP-B Mass % 20 20  5  5 Elastomer Mass % 15 15

TABLE 5 Examples 1 2 3 4 5 6 7 8 9 10 GMB-1 GMB-2 GMB-3 GMB-4 GMB-5GMB-6 GMB-7 GMB-8 GBD-1 GBD-3 Tensile stress MPa 163 163 163 160 151 150139 138 165 110 at break (23° C.) Bending strength MPa 238 238 238 234224 222 211 210 242 150 (23° C.) Flexural MPa 9100 9100 9100 9100 91009100 9100 9100 9100 6500 Modulus (23° C.) Charpy impact KJ/m² 93 93 9390 75 73 65 64 94 111 strength (23° C., no notch) Falling-ball cm — — —— — — — — — 60 cracks (1.9 kg) Weight average mm 8 8 8 8 8 8 8 8 8 8fiber length in composition Average aspect Average fiber 500 500 500 500500 500 500 500 500 500 ratio of fibers length/average fiber diameterWeight average mm 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 fiber lengthin molded article Average aspect Average fiber 156 156 156 156 156 156156 156 156 156 ratio of fibers length/average in molded fiber diameterarticle Comparative Examples 1 2 3 4 5 6 GMB-9 GMB-10 GMB-11 GMB-12GBD-2 GBD-4 Tensile stress MPa 133 135 127 121 135 90 at break (23° C.)Bending strength MPa 206 209 201 194 207 120 (23° C.) Flexural MPa 91009100 9100 9100 9100 6500 Modulus (23° C.) Charpy impact KJ/m² 60 61 5656 60 79 strength (23° C., no notch) Falling-ball cm — — — — — 35 cracks(1.9 kg) Weight average mm 8 8 8 8 8 8 fiber length in compositionAverage aspect Average fiber 500 500 500 500 500 500 ratio of fiberslength/average fiber diameter Weight average mm 2.5 2.5 2.5 2.5 2.5 2.5fiber length in molded article Average aspect Average fiber 156 156 156156 156 156 ratio of fibers length/average in molded fiber diameterarticle

TABLE 6 Comparative Example 7 8 9 10 Composition Top feedPolyolefin-based resin PP-A 58 58 58 58 Acid-modified C-3 2 2polypropylene-based resin C-11 2 2 Side feed Glass fiber GF-2 40 40 GF-340 40 Physical properties of composition Tensile stress at break (23°C.) MPa 127 124 128 126 Bending strength (23° C.) MPa 196 193 198 194Flexural modulus (23° C.) MPa 9200 9900 9900 9900 Charpy impact strength(23° C., no notch) KJ/m² 53 53 57 54 Weight average fiber length incomposition mm 0.35 0.35 0.35 0.35 Aspect ratio of the fibers incomposition — 35 35 33 33 Weight average fiber length in molded articlemm 0.25 0.25 0.25 0.25 Aspect ratio of fibers in molded article — 25 2525 25

Comparison of C-10 (Comparative Example 2) with C-1, C-2, and C-5(Examples 1, 2, and 5) reveals that a decrease in the amount oflow-molecular-weight maleic acid adducts leads to improved physicalproperties.

INDUSTRIAL APPLICABILITY

The fiber-reinforced resin composition according to the invention andthe molded article produced from the composition can be employed forautomobile parts (e.g. front end, fan shroud, cooling fan, engineundercover, engine cover, radiator box, side door, back door inner, backdoor outer, outer panel, roof rail, door handle, luggage box, wheelcover, handle, cooling module, air cleaner component, air cleaner case,and pedal); parts for bicycles or motorcycles (e.g. luggage box, handle,and wheel); household appliances (e.g. hot water washing toilet sheet,bathroom supplies, chair legs, valves, and meter box); electric tools,handle of a lawn mower, hose joints, resin bolts, and concrete frames.In particular, the fiber-reinforced resin composition and the moldedarticle produced from the composition can be suitably employed forautomobile parts including luggage boxes, side doors, air cleaner cases,back door inner, and front-end module (including fan shroud, fan, andcooling module), meter box, switch board, and engine cover.

1. A fiber-reinforced resin composition comprising: (A) apolyolefin-based resin; (B) glass fibers having (B1) an average diameterof 3 to 30 μm and (B2) an average aspect ratio of 50 to 6000; and (C) anacid-modified polypropylene-based resin exhibiting (C1) a change inamount of acid added, measured by Fourier transform infraredspectroscopy, before and after being treated in methyl ethyl ketone at70° C. for three hours of 0.8 mass % or less, and having (C2) a meltflow rate (load: 2.16 kg, temperature: 230° C.) of 20 to 2000 g/10 min;the composition containing the components (A) to (C) at such a ratio(mass ratio) that (B):[(A)+(C)]=5 to 80:95 to 20 and (A):(C)=0 to99.5:100 to 0.5.
 2. The fiber-reinforced resin composition according toclaim 1, wherein the polyolefin-based resin (A) is a polypropylene-basedresin.
 3. A molded article produced from the fiber-reinforced resincomposition according to claim
 1. 4. A molded article produced from thefiber-reinforced resin composition according to claim
 2. 5. A maleicacid-modified polypropylene-based resin exhibiting (C1) a change inamount of acid added, measured by Fourier transform infraredspectroscopy, before and after being treated in methyl ethyl ketone at70° C. for three hours of 0.8 mass % or less, and having (C2) a meltflow rate (load: 2.16 kg, temperature: 230° C.) of 20 to 2000 g/10 min.